Course and burden of risk symptoms and criteria of psychosis in the community: 5- to 10-year follow-up of the Bern Epidemiological At-Risk (BEAR) and the Bi-national Evaluation of At-Risk Symptoms in children and adolescents (BEARS-Kid) studies

Background and rationale: First-episode psychoses are commonly preceded by a prodromal phase in which clinical high risk (CHR) symptoms, multiple other mental problems, and psychosocial deficits already occur. Currently, two sets of CHR criteria are used by early detection centres: (i) symptomatic ultra-high risk and (ii) basic symptom criteria. Both were associated with the conversion to full-blown psychosis over >4 years in 35-60% of selected, non-representative samples of help-seeking CHR patients with reduced rates in children and adolescents as well as services with extensive outreach activities. Longitudinally, high rates of subsequent non-psychotic severe mental disorders, lower long-term functioning, and high remission rates of CHR criteria/symptoms were reported. Because of the limited specificity (e.g. about 2/3 of CHR patients never converting to psychosis) and the potential for stigmatisation, the rationale of specialized early detection of psychoses and clinical validity of CHR criteria have recently been questioned with the proposal that these criteria might better be regarded as transdiagnostic severity or pluripotential markers of risk.Objectives and aims: The overall objective is to assess the 5- to 10-year outcome of persons in the community with CHR symptoms/criteria (RISK) at baseline, i.e., at age 8 to 40 years, in comparison to those without (CONTROL). The main question is if CHR criteria predict lower psychosocial functioning over and above the assessment of general psychopathology, and how far this is influenced by age. After adjusting for multiple testing, small group differences will be detectable with a minimum power of 95%. Further aims are to examine (1) the persistence rate and clinical relevance of CHR symptoms (i.e., their relation to functioning, mental disorders, need for care and life satisfaction), (2) predictors of their persistence and new occurrence, and (3), (self-)stigmatisation experiences of RISK and CONTROL with mental problems. Potential predictors and secondary outcomes studied in addition to CHR symptoms, criteria and general psychopathology are sociodemographics, help-seeking, life satisfaction and somatic health.Methods: At baseline, both a 16- to 40-year-old (N=2,683; BEAR sample) and an 8- to 17-year-old (N=235; BEARS-Kid sample) random community sample of the Canton Bern were interviewed for CHR symptoms/criteria. A quarter of participants had reported risk symptoms (RISK) with 2.4% meeting CHR criteria; they were not informed of the “result”. In a first 3-year follow-up of the BEAR sample (FU1), 1,263 participants were sampled, and 834 interviews (434 RISK, 400 CONTROL) were completed. The re-contact rate was 78.8%, response rate 66.4%, and refusal rate 12.0%. Five converters to psychosis (0.5%) - all of RISK - were identified. Within two years, one person of the BEARS-Kid sample - also of RISK - had developed a psychosis; the drop-out rate was 11%. Thus, 1,084 participants of the BEAR FU1 and 194 participants of BEARS-Kid, i.e. N=1,278 participants will be contacted for FU2, following established earlier procedures. Expecting a refusal rate of 12% and a non-contact rate of 20%, approximately 860 participants are expected to participate in FU2.Expected results and impact: Earlier results of the BEAR study already indicated that CHR symptoms/criteria possess some clinical relevance in the community to predict an increased risk for conversion to psychosis. It is still unclear if CHR symptoms or criteria have a long-term clinical relevance in terms of predicting mental disorders and poor functioning over and above general psychopathology and outside clinical samples. The study’s results will have a large clinical and economic impact, as they will influence diagnostic and therapeutic considerations in early detection and intervention strategies by deciding if they should reach out into the community and actively bring persons with CHR symptoms into treatment, or not. This question is relevant internationally and nationally, as early detection of psychoses is already widely applied in Switzerland and other countries.